Harmonic Propulsion And Harmonic Controller

ABSTRACT

A device and method for propelling objects using periodic or harmonic vibrations is described. The device comprises a flexible substrate or surface and a source of vibrational energy that is applied to the substrate or surface. Specific embodiments include a device which can move along a flat surface, which can climb a smooth vertical or slanted wall, which can move along a ceiling while suspended upside down, which can climb up a smooth hollow tube, or which can move through liquids.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending, commonly assigned U.S.patent application Ser. No. 10/536,479, filed Oct. 3, 2005, which is aNational Phase filing of PCT Patent Application No. PCT/US2004/032702,filed Sep. 30, 2004, which is based upon commonly assigned U.S.provisional patent application Ser. No. 60/507,667, filed Sep. 30, 2003,all of which are incorporated herein in their entirety.

FIELD OF THE INVENTION

The present invention generally relates to a method for moving objects.The present invention specifically is directed to propelling objects byusing periodic or harmonic vibrations. Embodiments of the presentinvention include a method to move an object along a flat surface(translating horizontally), to move an object up a smooth vertical wall(climbing vertically), to move an object along a ceiling while theobject is upside down relative to its position in normal horizontaltranslation, to climb inside a smooth hollow tube, to swim throughliquids, and to rotate. The present invention is also directed todevices which execute the various movements.

BACKGROUND OF THE INVENTION

Historically, the usual means for propelling objects along the groundhas been by employing wheels. Typically at least one wheel is made tomove by means of a motor. The wheel so driven exerts force on the groundas it turns, and the object to which the wheel is attached will moveforward. A common example of such a method is that of propulsion ofautomobiles. Another means for propelling or moving objects is apropeller. A propeller will push against a fluid in which an object isimmersed and thereby propel the object forward. Simple examples would bethe motion of an airplane propeller against the fluid air or the motionof a boat propeller against the fluid water. A different means ofpropulsion is inertial reaction in which mass is expelled in onedirection, causing an object expelling the mass to move in the oppositedirection, by virtue of conservation of linear momentum. A simpleexample of such motion would be the motion of a rocket or a jetairplane.

Although there are numerous examples of the use of wheels, propellers,and reaction engines to impart translation motion, there appear to berelatively few examples of the use of vibrations to induce motion. Ofthe few vibratory examples, most involve the use of vibrations impartedto the entire surface on which the moving object is travelling. One suchexample is the use of vibratory conveyor belts to move grain or smallparts in manufacturing operations. There is also a toy sports game inwhich miniature football players are moved along a playing field, whichis a sheet of metal, by vibrations to the entire playing field inducedby an electromechanical motor (such as a buzzer). However, there are nodevices wherein there is a self-contained and mobile source ofvibrations that cause an object to move translationally in a directablemanner.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a method and device forharmonic propulsion.

It is also an object of the invention to provide a method and device forpropelling and/or controlling objects by use of periodic or harmonicvibrations.

It is a further object of the invention to provide a method and devicefor imparting translational motion to an object.

It is a yet further object of the invention to provide a method anddevice for imparting translational motion to an object on a surface byvibrating the object to produce harmonic motion and coupling thevibration to the surface in an asymmetric way

It is a yet further object of the invention to provide a method anddevice to move an object along a flat surface, to move an object up avertical wall, to move an object along a ceiling, to move an objectthrough a smooth hollow tube, to move an object through a liquid orfluid, or to cause an object to rotate.

These and other objects of the invention will become more apparent fromthe discussion below.

SUMMARY OF THE INVENTION

According to one aspect of the invention, vibratory motion is used toperform the functions of devices described herein, namely, to move alonga level surface, to climb up a smooth vertical or slanted wall, to moveupside down on a ceiling, or to climb up a hollow tube. Another aspectof the invention comprises a solution to the problem of controlling thedirection of such moving devices. Without directional control, theutility of a moving device is much reduced; and, with directionalcontrol, the method and device for which is taught by the presentinvention, it becomes possible to build devices which can be used forexploration of intricate spaces, under either remote control or controlbased on an on-board set of sensors and decision-making circuits. Adevice according to the invention is expected to be have variousapplications. One potential use is in the in the medical field, forexample, in or with a partly or wholly self-propelled endoscope or otherinvasive medical device.

A great advantage of vibratory or harmonic propulsion is that suchdevices may be very small and simple compared to more conventionaldevices, such as wheeled devices. This is because this form ofpropulsion does not require axles, bearings, transmissions, or evenwheels, as are needed for wheeled devices. This form of propulsion doesnot require propellers or jet engines. The present invention requires asystem with a source of vibrations and a driving surface, which comes incontact with the surface upon which the device is moving.

Also, unlike wheels or treads (as in a tank), harmonic propulsion can beeffected on any or all surfaces of the device, instead of being limitedto the aspects of the device (the driving surface of the wheels ortreads). Therefore, it becomes very easy using harmonic propulsion tobuild devices which can, for example, ascend the inside of hollow pipessince the device can obtain propulsion from the entire circumference ofthe pipe. Also, the surface of vibration can be adjusted as to itsstiffness and texture so that the device can move on a great variety ofterrain (for example, hard, smooth, dry ground versus softer wetground). In one embodiment, it is envisioned that this technology willallow for the development of a practical self-propelled endoscope toexplore a patient's gastrointestinal tract or another corporeal channelor site.

In its simplicity and with few moving parts, the present inventionovercomes the problems of the prior art. The present invention describesa device and method to cause an object to move translationally byimpartation of vibrational energy.

One embodiment of the invention is generally directed to impartingtranslational motion of an object by application of vibrations,preferably harmonic vibrations.

Another embodiment of the invention is a device to effect translationalmotion that comprises a source of harmonic or periodic mechanical oracoustic vibrations, a vibrating surface whose modes of vibration areexcited by the source of vibrations, and a symmetry breaking element.

Another embodiment of the invention concerns a method to effecttranslational motional comprising the steps of applying harmonic orperiodic vibration to an object, exciting modes of vibration in asurface, and directing the translational motion of the object by usingsymmetry breaking elements. The present invention specifically disclosestypes of vibration sources, types of vibrating surfaces, and types ofantisymmetry elements.

Other embodiments of the present invention include methods to effecttranslational motion from traveling waves, translational motion fromstanding waves, wall climbing motion, directional control usingvibrating surfaces (“focusing surfaces”) which interact with obstacles,and directional control using eigenmodes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of one embodiment of the invention;

FIG. 2 is a perspective view of an embodiment of the invention on avertical surface; and

FIG. 3 is a schematic cross-sectional view of an embodiment of theinvention having a distinct antisymmetry element.

DETAILED DESCRIPTION OF THE INVENTION

In general, the present invention represents a novel approach to effecttranslational motion by application of vibrations. More particularly,aspects of the invention are directed to a device to effect such motionand a method to produce such motion.

A device according to the invention employs vibratory motion emanatingfrom the device itself, to effect translational motion. Such a devicecomprises a source of harmonic or periodic mechanical or acousticvibrations. This vibration source must be energetic enough to produceamplitudes of vibration which can actually cause movement of the device.Suitable vibration sources include, for example, the following:

(1) an electric motor which is fitted with an eccentric cam. A preferredaspect of a motor which rotates an eccentric weighted cam is thattraveling waves can be produced, since the motor-cam combination tendsto produce a rotating or twisting motion in addition to an up-down andside to side motion;

(2) an electromechanical buzzer consisting of an electromagnet and aspringy steel vibrating reed. Such devices are preferred for producingstanding waves;

(3) an electromagnetic audio speaker;

(4) a piezoelectric speaker or bending element; and

(5) a gas under pressure escaping from a nozzle, which is used tovibrate a reed or drive some sort of oscillating device such as apiston-cylinder combination. If the source of the gas is some sort ofcombustion process, then it is possible to obtain a much greater powerto weight ratio than is possible with battery powered motors. Anothermethod of obtaining gas under pressure would be to exploit a phasechange of a particular substance, e.g., the change of solid CO₂ (“dryice”) into a gas at room temperature. Yet another means of obtaining agas under pressure would be some sort of chemical reaction, e.g., thebreakdown of acetic acid and sodium bicarbonate into CO₂ (gas) andwater.

A device according to the invention comprises a vibratable or vibratingsubstrate whose modes of vibration are excited by the source ofvibrations. The vibrating substrate needs the correct stiffness (modulusof elasticity) and mass density to vibrate. It will also need to havethe correct size and shape so that its normal modes of vibration canresult in forward, left, and right motion of the device. Size and shapeof the device are selected to optimize outcome. Typical shapes includecircular, rectangular, oval, and square, circular being preferred. Ithas been found empirically that plates with these shapes have normalmodes of vibration which lend themselves to forward motion with theability to be directed to the right or to the left as desired. Someparticular embodiments are a thin plastic sheet, a thin brass sheet, anda thin Styrofoam sheet, having a thickness from about 0.02 to about 0.20inches thick, preferably from about 0.05 to about 0.15 inches thick. Ina preferred embodiment of the invention the substrate will be flat orsubstantially flat where the surface of the substrate facing ahorizontal, slanted, or vertical surface may have a slightly angledouter periphery or “lip”, which will extend all, or substantially all,the way around the outer periphery of the substrate.

Preferably a device according to the invention comprises an“antisymmetry element” (or symmetry breaking element) which will breakthe symmetry of the vibrating motion relative to the ground and therebyproduce a net translational movement. This antisymmetry element can bean arrangement of projections or bristles situated at an angle to thevibrating surface which functions to break the symmetry of the vibratingmotion relative to the ground and thus produce a net translationalmovement. The antisymmetry elements are, in general, at an angle to thevibrating surface, which angle will preferably be other thanperpendicular to the vibrating surface. The elements may consist ofbristles, semi-stiff pins, bumps, or any textured projection. Thepurpose of these antisymmetry elements is to convert the symmetricalstanding waves of the vibrating surface into propulsive movements of thedevice. Specific examples of such embodiments include, for example,flexible brush bristles, which are curved backward; small spines orspicules embedded in a flexible matrix; fins; and a conformable mat.

In addition to providing translational movement, the antisymmetryelement contributes to a control mechanism whereby changing thefrequency of the harmonic vibratory motion will cause direction of thedevice to change. In addition, in other embodiments of the invention,the vibrating surface may be segmented and/or there could be more thanone source of vibratory energy, so that there could be translationalmovement as well as directional control.

There are at least five distinct aspects to the invention:

Translational Motion from Travelling Waves

Traveling waves, which are produced in the vibrating surface, canobviously produce translational motion as these waves progress from oneend of the device to the other end. By alteration of the direction ofthese traveling waves, steering or directional control can be produced.

Translational Motion from Standing Waves

Vibrations or waves in a solid or liquid medium can be either standingwaves or travelling waves. From everyday experience one knows thattraveling waves, such as ocean waves, can be used to propel objects suchas, for example, boats or surfers. Standing waves, however, produce onlyrepetitive motion, which does not result in any net displacement ofmaterial, or translational motion. An example of this would be thestanding waves produced on the string of a musical instrument. If astanding wave is made to impinge on the ground, there would be no netmotion in any direction since the displacements of the wave tending toproduce motion in one direction would be cancelled out in the next halfcycle by the return motion of the wave in the opposite direction.However, it is possible to use standing waves to effect nettranslational motion if the waves can be coupled to the ground inantisymmetric way so that a force in one direction during one part ofthe wave cycle that is not counterbalanced by an equal and oppositeforce in the other direction during the next part of the cycle. Thisasymmetry is produced by the antisymmetry elements on the vibratingsurface, which are at an angle to the surface.

This translational motion may be used to propel the device on a flatsurface (one surface of contact between device and substrate), in awalled channel without a roof (three surfaces of contact), in a hollowtube (contact on all lateral surfaces), and in liquids either on thesurface or submerged.

Wall Climbing Motion

Certain standing waves, particularly those with circular symmetry, canproduce a suction or vacuum effect as the vibrating surface is liftedaway from the surface during one part of the vibratory cycle andslightly pushed into the surface during another part of the cycle. Whenthe surface is being accelerated towards the wall, a slight positivepressure is produced under the plate, which is more than overcome by theinertial forces, which are pressing the plate against the wall. Themotion of the plate relative toward the wall may also simultaneouslyproduce some net translational motion. In the next part of the cyclewhen the plate is being accelerated away from the wall, a vacuum isproduced under the plate, which tends to hold it to the wall but now theinertial force tends to pull the plate away from the wall. A new wallholding effect depends on the correct balance between the vacuumproducing part of the cycle with the inertial forces, which try toremove the plate from contact with the wall. If the motion when theplate is being accelerated away from the wall is not too violent, therewill be production of a vacuum between the plate and the wall, whichwill more than compensate for the inertial force, which tends to throwthe plate away from the wall.

Directional Control Using Vibrating Surfaces (“Focusing Surfaces”) whichInteract with Obstacles

The essential understanding here is that focusing surfaces which areconcave relative to the obstacle encountered will tend to steer thedevice toward the obstacle, while focusing surfaces which are convexfocusing surfaces tend to steer the device away from the obstacle. Thissteering ability is enhanced by the vibrating nature of the basic motionof the device, as the vibrations tend to re-align the device toward (oraway) from the obstacle.

Directional Control Using Eigenmodes

Directional control can be achieved by using certain normal modes of thevibrating surface. The best combination of normal modes to produce theability to turn left or right would be two modes which are mirror imagesof one another and which are asymmetric around the longitudinal axis ofthe vibrating surface. When the vibrating surface is equipped withappropriate antisymmetry elements, the device will turn either to theleft or to the right depending on which normal mode is active. A normalmode (“eigenmode”) can be selected by vibrating the surface at thespecific frequency corresponding to that mode (“eigenfrequency”). Thefact that there is a one to one correspondence between eacheigenfrequency and each normal mode is known from the physics of wavemotions and the solutions of the wave equation.

Embodiments within the scope of the invention include:

-   -   (1) a device which propels itself by means of its own vibratory        motion;    -   (2) a device which can move on a flat surface;    -   (3) a device which can move on a channeled surface;    -   (4) a device which can move by adhering to a wall or other        vertical or slanted surface;    -   (5) a device which can move by adhering to a ceiling or other        horizontal surface;    -   (6) a device which uses a vibrational source to create standing        waves in the device;    -   (7) a device which uses a vibrational source to create traveling        waves in the device;    -   (8) a device which uses “antisymmetry” texturing of the        vibrating surface to effect translational motion from standing        waves; and    -   (9) a device which can use a balance of inertial and suction        forces to adhere to a wall or ceiling and also translate (move)        along that wall or ceiling.

In another embodiment of the invention, the vibration-producing elementof the device comprises an electromechanical buzzer, a rotatingeccentric cam on an electric motor, an escaping gas which vibrates areed, an element which produces standing waves in the device, an elementwhich produces traveling waves in the device, a device wherein standing(stationary) waves can produce translational motion by means of elementsat an angle to the vibrating surface of the device, or a combination oftwo or more thereof, or the functional equivalent of one or morethereof.

Antisymmetry elements, as discussed above, produce a net force in onedirection when averaged over the entire vibratory cycle. Such elementsmay be, for example, bristles, periodic elevations, regular or irregularprojections, or conformable surfaces.

A device according to the invention can be controlled or steered bymeans of special surfaces called “focussing surfaces”, by means ofvarying the frequency of vibration to select a particular eigenmode, bymeans of selective damping of the vibrating plate at a nodal line of adesired eigenmode in the case of a standing wave vibrational source, bychanging the direction of rotation of the vibrating device in the caseof traveling waves.

The invention can perhaps be better appreciated by making reference tothe drawings. FIG. 1 represents an embodiment of the invention whichcomprises a circular substrate 10 having a source of vibratory harmonicmotion or motor 12 centered thereon. Adjacent motor 12 is a batteryholder 14 containing two AA batteries 18. Two wires 20 lead from batteryholder 14 to a switch 22, which switch 22 is electrically connectedthrough wires 24 to motor 12. Activating switch 22 closes the electricalcircuit comprising batteries 18 and motor 12 and causes motor 12 tovibrate.

Motor 12 can comprise any known or future source for impartingvibrational energy, to cause harmonic motion. Motor 12 has to besufficiently small and efficient to impart vibrational energy but notweigh too much that it negates the vibrational effect or causes thedevice to slide or fall off a non-horizontal surface. A representativemotor 12 is a commercially available pager motor, which providesvibration in the frequency of from about 5 to 20 cycles per second.

Substrate 10 should be a flexible but rigid surface that can vibrate inresponse to the vibrations from motor 12. Typical materials useful forsubstrate 10 include polymers, metal, ceramics, and the like. Substrate10 should be thick enough to support motor 12 but thin enough tovibrate.

Substrate 10 can be of almost any shape or size, dependent upon thestrength or power of motor 12. The weight of motor 12 plus the batterieswould also be a factor. The bottom surface 30 of substrate 10 ispreferably substantially flat, although a slightly concave or pie-plateor FRISBE-shape surface will work as well.

FIG. 2 is a cross-sectional view of the device shown in FIG. 1 inposition on a vertical surface 32. With the motor 12 activated, thedevice 34 will either remain in approximately one position, or it mayslowly move in a direction along surface 32. If an external lateralforce is applied to motor 12 or substrate 10, device 34 will tend to goin that direction. Also, device 34 may be configured as discussed aboveso that vibratory action may result in directional control.

FIG. 3 is a schematic view of an embodiment of the invention where thedevice 40 comprises a housing 42 containing a vibrational energy source(not shown specifically) and a power supply (not shown specifically),such as one or more batteries, and a substrate 44. Extending from thelower surface 48 of substrate 44 are bristles 50, which are shown at anangle of about 30° from normal to horizontal surface 52. Preferablybristles such as bristles 50 will be from about 45 to 85° from normal.Optionally bristles 50 could be slightly curved and are preferablycomprised of a suitable flexible polymeric material.

EXAMPLES Example 1

The device comprises a Styrofoam pie plate (9 inches in diameter, ofcentral depth ¾ inch, with an edge at the circumference of widthapproximately one-half inch), an electrical motor with an eccentricweight, and 2 Ni—Cd batteries (AAA size). The motor and batteries areplaced on the underside of the pie plate.

In one use, the device, with the pie plate upside down, translated withthe circumferential edge in contact with a surface. This devicetranslated in a vertical direction along a wall, in an embodiment termed“wall crawling pie plate.”

In another use, the motor and batteries can be placed in an enclosure,such as a film can. The device, with the pie plate upside down,translated with the circumferential edge in contact with a surface.Specifically, the device can translate along a surface, such as aporcelain tub surface, underneath water.

Example 2

The device comprises an approximately flat 3 inch diameter,approximately 1 mm thick, circle or approximate circle of material(which can be cut, for example, from the bottom of the 9″ diameterStyrofoam pie plate), a pager motor, and a power source. The powersource can be wires connected to the motor which lead to a batteryremote from the 3 inch diameter circle.

On energizing the motor and creating vibrations, the device translatedalong a surface.

Example 3

The device comprises a ping pong ball with a hole, a motor, and a powersource. The motor and power source can be placed within the ping pongball. On energizing the motor and creating vibrations, the device spinswhen placed in a cup of water. It is believed that this is throughrotational traveling waves.

Example 4

The device comprises a foam wheel with a motor and a power source. Onenergizing the motor and creating vibrations, the foam wheel revolved.

Example 5

The device comprises a piece of scrub brush with a motor and a powersource. The motor is attached to the portion of the scrub brush oppositethe bristles. On energizing the motor and creating vibrations, the scrubbrush moved forward.

Example 6

The device comprises a motor, potted in a container, with a power sourceor leads to a power source, wherein bristles are attached to the scrubbrush. This device climbed vertically in a cardboard tube even carryingits own battery.

Example 7

The device comprises a motor with a power supply, a brass sheet, andbristles attached to the brass sheet on the side opposite to the sidewith the motor. Depending on the frequency of the motor, the device,when placed on a surface, turned left, turned right, or went straightahead. The bristles are used to break symmetry.

The preceding specific embodiments are illustrative of the practice ofthe invention. It is to be understood, however, that other expedientsknown to those skilled in the art or disclosed herein, may be employedwithout departing from the spirit of the invention or the scope of theappended claims.

1. A device comprising: a flexible substrate or first surface and atleast one source of vibrational energy attached to or in communicationwith the flexible substrate or first surface, wherein vibrational energyis applied to the flexible substrate or first surface to cause periodicmotion in the flexible substrate or first surface and the device iscapable of translational motion along a second surface or through afluid.
 2. The device of claim 1, wherein the vibrational energy isharmonic.
 3. The device of claim 2, wherein the vibrational energycauses the substrate or surface to flex in a harmonic fashion.
 4. Thedevice of claim 2, wherein at least one of the at least one source ofvibrational energy imparts vibrations to said substrate or first surfaceto cause said device to move in a translational fashion.
 5. The deviceof claim 1, wherein the second surface is other than horizontal.
 6. Thedevice of claim 1, wherein a change in frequency of the vibrationalenergy causes the direction of the motion of the device to change. 7.The device of claim 1, which also comprises an asymmetry element.
 8. Thedevice of claim 7, wherein the asymmetry element comprises bristles,spines or spicules embedded in a flexible matrix, regular or irregularprojections, fins, or a conformable mat.
 9. The device of claim 8,wherein the asymmetry element comprises bristles.
 10. The device ofclaim 1, wherein the flexible substrate is circular, rectangular, oval,square, or hemispherical.
 11. The method of claim 1, wherein theflexible substrate has first and second substantially parallel planarsurfaces.
 12. A method for imparting translational motion to an objecton a first surface or in a fluid, the object comprising a flexiblesubstrate having at least one substantially flat surface and a source ofvibrational energy attached to or in communication with at least one ofthe at least one substantially flat surface to apply vibrational energyto the flexible substrate, said method comprising the steps of: (a)vibrating the object to produce harmonic vibration; and (b) coupling thevibration to the first surface or fluid in an asymmetric way to producetranslational motion by the object.
 13. The method of claim 12, whereinan asymmetry element produces a net force in one direction when averagedover the entire vibratory cycle.
 14. A method for impartingtranslational motion to an object having a flexible substrate or a firstsurface and a source of vibrational energy on a second surface or in afluid, said method comprising the steps of: (a) applying vibrationalenergy to the object to produce harmonic vibrations in the flexiblesubstrate or first surface; and (b) coupling the vibrations to thesecond surface in an asymmetric way to produce translational motion bythe object.
 15. The method of claim 14, wherein a force in one directionduring one part of the wave cycle is not counterbalanced by an equal andopposition force in the other direction.
 16. The method of claim 14,wherein an asymmetry element produces a net force in one direction whenaveraged over the entire vibratory cycle.